1. Technical Field
The present disclosure relates to surgical cannula assemblies and more particularly, to fluid flow control selector apparatus for surgical cannulae.
2. Description of Related Art
Insufflatory surgery involves filling a body cavity with a pressurized gas, normally CO.sub.2, to maintain the cavity under a certain predetermined pressure. One way of performing the surgery is by first puncturing the skin in a desired body cavity region with a needle. The needle, typically a Verres needle, includes a stylet which introduces an insufflation gas into the body cavity to inflate it.
A trocar is then used to puncture the body cavity. The trocar is inserted through a cannula or sheath, which cannula partially enters the body cavity through the incision made by the trocar. The trocar may then be removed from the cannula, and a surgical instrument such as an endoscope, graspers, clip appliers, forceps, etc., may be inserted through the cannula to perform the desired task within the anatomical cavity.
Various types of cannula or trocar assemblies are provided with valves for maintaining a certain gas pressure in the cavity when the trocar or other surgical instrument is removed from the cannula. One example of such an assembly is disclosed in U.S. Pat. No. 4,943,280 to Lander which features a cannula assembly having a flapper valve that is biased toward a closed position when no surgical instrument is inserted in the cannula assembly. In such devices, in order to rapidly desufflate the body cavity, the flapper valve may be selectively biased to the open position by a lever provided on the exterior of the cannula housing.
Another type of cannula or trocar assembly that maintains the seal of the insufflated body cavity utilizes one-way valve members, for example, elastomeric duck bill valves, to effectively retain the insufflation gases. Such devices have a stop-cock valve with a single fluid passageway located distal of the duck bill valve to facilitate the insufflation or desufflation of fluids from the body cavity. However, in order to desufflate, the insufflatory tubing must generally be removed therefrom.
One disadvantage of such cannula assemblies is that the maximum rate of insufflation and desufflation are equal due to the diameter of the single fluid passageway formed by the stop-cock with the channel of the cannula housing. Such devices, do not provide the user with the ability to selectively open the duck-bill in a similar manner as for the flapper valve, disclosed in U.S. Pat. No. 4,943,280 to Lander. Therefore, a need exists to provide a surgical cannula or trocar assembly which provides the user with a stop-cock assembly having a plurality of fluid flow paths to provide the ability to selectively insufflate or desufflate the body cavity without the necessity of adjusting or repositioning insufflatory tubing or the like.